In general, this kind of writing tool, for example, a coating tool for correcting wrong letters by coating correction liquid, is constructed such that e.g., a rotary member held within the extremity end of the tip is biased by a spring and closely contacts the inward extremity edge of the tool tip closing the extremity end of the tip and preventing correction liquid from being discharged. In turn, the rotary member projecting from the extremity end of the tool tip maybe retracted and spaced apart from the inward extremity edge of the tip, against the spring to open the extremity end of the tip, whereupon the correction liquid in the liquid tank is discharged from the extremity end.
In the prior art, this kind of writing tool, as shown in FIG. 16, an inner cylinder 32 for pressurizing and compressing air is arranged within a cap 30 to closely contact an outer periphery of an extremity end 31, The cap 30 is pushed and loaded against the extremity end 31, air is pressurized and compressed in the inner cylinder 32, and the rotary member 34 held in the extremity end of the tip 33 is retracted inwardly toward the tip. The rotary member 34 is thereby moved away from the inward extremity edge of the tip 33, and the compressed air in the inner cylinder 32 is fed into the liquid tank 35 so as to increase an inner pressure in the liquid tank 35 (e.g., Japanese Utility Model Laid-Open publication No. Hei 6-39169).
Thus, as described in the paragraphs 13 through the 15 of page 7 of the laid-open specification, the prior art writing tool is constructed such that when the cap 30 is loaded in respect to the extremity end 31, the inner cylinder 32 of the cap 30 closely contacts the outer periphery of the extremity end 31 to make a sealed space preventing air leakage within the inner cylinder 32, and the air in the inner cylinder 32 is pressurized and compressed under the reduced volume of the sealed and closed space. Then, when the air in the inner cylinder 32 is pressurized and compressed, the rotary member 34 projecting from the tip 33 abuts a tongue 37 of a resilient valve opening member 36 arranged in The cap, the rotary member is then is retracted against the spring by the force of the tongue 37, in such a manner that the rotary member 34 is moved away from the inward extremity edge of the contacted tip 33, thereby feeding the compressed air in the inner cylinder 32 from the clearance formed between the rotary member 34 and the inward extremity edge into the liquid tank 35, pressurizing the liquid tank 35.
However, the tongue 37 of the valve opening member in the cap is cantilevered, this structure achieved by cutting and raising the cylindrical part of the valve opening member 36 inwardly. Accordingly, when the cap is loaded in respect to the extremity end, the rotary member projecting from the tip extremity end is retracted by means of the pushing force of the tongue against the spring. Accordingly, the pushing force of the tongue becomes attenuated within a short period of time when the cap is repeatedly fixed and removed and eventually, the rotary member is not retracted inwardly toward the tip against a the spring under the attenuated pushing force of the weakened tongue. Disadvantages of poor positive operation and poor stability result.
In order to cut and raise the tongue from the valve opening member, machining is required. Further when air in the inner cylinder is pressurized and compressed, the valve opening member must be assembled and arranged within the cap in a positional relation where the rotary member abuts the tongue. The assembling operation is there troublesome and expensive.